Engine cylinder heads distort sufficiently under operating thermal and mechanical loads to misalign the valve seat--valve guide relationship. This misalignment causes either very high mechanical stress in the valve head when it is seated and/or prevents the valve from seating completely. Improper seating may cause flash heating or cooling due to exhaust gases or intake air rushing through small gaps between the valve and seat resulting in uneven heating or cooling of the head thus thermally stressing the head of the valve. U.S. Pat. No. 5,592,913 describes an exhaust valve with a tapered stem portion that has a head portion with a frustoconical seat. A trumpet like portion that extends from the seat portion to a tapered portion, which tapers outwardly to a cylindrical portion that is slidably disposed in a valve guide. A weld joins the tapered portion to the cylindrical portion. This juncture is always disposed in the valve guide to prevent scuffing and seizure at the inlet of the valve guide due to differential thermal expansion as the head and stem portions are formed of different alloys.